Identify the pair of reactions undergoing disproportionation from the following.

• A
  $2 H_2O_2 \rightarrow 2 H_2O + O_2$ and $Cl_2 + 2 NaOH \rightarrow NaCl + NaOCl + H_2O$
• B
  $P_4 + 3 NaOH + 3 H_2O \rightarrow PH_3 + 3 NaH_2PO_2$ and $Cl_2 + 2 NO \rightarrow 2 NOCl$
• C
  $Cl_2 + 2 KBr \rightarrow 2 KCl + Br_2$ and $5 Cl_2 + I_2 + 6 H_2O \rightarrow 2 IO_3^{-} + 10 Cl^{-} + 12 H^{+}$
• D
  $Pb_3O_4 + 8 HCl \rightarrow 3 PbCl_2 + Cl_2 + 4 H_2O$ and $P_4 + 3 NaOH + 3 H_2O \rightarrow PH_3 + 3 NaH_2PO_2$